Frank's wrote:
Assuming a 7 ft monopole, with a lumped element inductor
(located in the middle of the vertical) of Q = 500,
and 100 W input. The total radiated (sky wave) power is 1.4 W.
The gain is -12.7 dbi with a take-off angle of 23 degrees.
At resonance the input impedance is 14 ohms.

And the Q of a hamstick is probably a lot closer to 50
than to 500. Someone else reported the hamstick as -20 dBd.
--
73, Cecil http://www.w5dxp.com

And the Q of a hamstick is probably a lot closer to 50
than to 500. Someone else reported the hamstick as -20 dBd.

I would think it would be hard to design a coil with a Q of 50.
I tried to find a picture of a Hamstick to estimate the Q,
but no luck. Anyway, assuming the Q is 50, NEC returns
the following results:

Structure efficiency - 5%
Total radiated sky wave (with 100 W in) = 180 mW.
Input impedance - 112 ohms.

73,

Frank

Structure efficiency - 5%
Total radiated sky wave (with 100 W in) = 180 mW.
Input impedance - 112 ohms.

PS -- and the gain is -23 dbi at a 20 deg TOA.

Frank's wrote:
PS -- and the gain is -23 dbi at a 20 deg TOA.

Someone measured it at -20dBd so that may be
fairly accurate.
--
73, Cecil http://www.w5dxp.com

On Thu, 01 May 2008 15:49:00 -0400, Buck
wrote:


If I have a low dipole about 10 feet off the ground for 75 meters,
would it be better if I put a hamstick 75 meter vertical up and
connect the dipole wires to the ground side for a vertical?

Buck
N4PGW


In another forum, I was informed that the signal for the vertical was
very low at every angle compared to the dipole.

One of the things i was thinking about was if it would be beneficial
to add a good ground radial to the mobile whip on the car, once
parked. however, it is obvious that if one can raise, even 10 feet, a
full sized 1/2 wave dipole, it would produce much better results being
left in the dipole configuration.

Thank you to all who participated. (Even to the one who simply said
"NO"). that was a short, sweet and to the point answer.

73 for now
Buck
n4pgw

--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."

It just occurred to me that I have over looked something that might have
some use in this discussion. I just realized that this thread is about a
low dipole compared to a vertical Hamstick antenna. I reported that I have
compared a Hamstick dipole to a full size dipole and that it was down 20db
from the full size dipole. I can also report on a Hamstick vertical
compared to a full size dipole on 80m. For some years I’ve been using a
phased vertical system as a receive antenna on the 80m SSB Dx window. It is
2 Hamstick’s spaced 1/16 wave apart and feed 90 degrees out of phase with a
relay system that lets me switch directions. As a receive antenna it works
very well. A friend that has a 900’plus beverage tells me that it compares
very well. For me it gives me about at 15db signal to noise advantage over
my transmit dipole. The front to back is also about 20db in the most
favorite direction. But here is the part that is germane to this thread.
The signal level compared to the dipole is still about 20db down. I don’t
care as receivers have a lot of extra gain and the increase in signal to
noise makes all the difference. I don’t have much of a ground system, just
4 10’ radials under each vertical but putting down a good ground will not
make up 20db, no way. The main advantage that a beverage has over this
antenna is that it will cover several ham bands and the Hamstick verticals
are only good for about 100Khz around the DX window but that is all I want
and it fits in my yard as the spacing is only about 30’.
So I can say that a phased hamstick vertical on 80m with a poor ground is
also about 20db down from a full size dipole at 40’.

John, W3JXP

John Passaneau wrote:
So I can say that a phased hamstick vertical on 80m with a poor ground is
also about 20db down from a full size dipole at 40’.

It all makes good sense. The best 75m mobile antennas
are about 10 dB down from a 1/2WL dipole. The hamstick
is about 10 dB down from the best 75m mobile antennas.
--
73, Cecil http://www.w5dxp.com

On May 5, 10:19 am, Cecil Moore wrote:
John Passaneau wrote:
So I can say that a phased hamstick vertical on 80m with a poor ground is
also about 20db down from a full size dipole at 40’.

It all makes good sense. The best 75m mobile antennas
are about 10 dB down from a 1/2WL dipole. The hamstick
is about 10 dB down from the best 75m mobile antennas.
--
73, Cecil http://www.w5dxp.com

It's the lack of a decent radial system which makes me
look at it in a negative manner..
It's quite possible for the short vertical to outplay the
low dipole for DX, but... I don't see it happening with
only 2 radials and low to the ground.
The hamstick would actually work better mounted on a
vehicle than it would in that 2 radial scenario I bet.
So it's more the ground radial problem, rather than
the short radiator itself.
On 40m, my mobile outplays my 35-40 ft high dipole
to DX. But, I don't know if that would be the case with
two low radials, vs the usually better RF ground that
my vehicles provide.
With a low vertical on 80m, two radials ain't gonna
get it done as far as avoiding ground loss.
And the short vertical makes things even more critical.

For NVIS use, the low dipole would *smoke* the short
vertical with two radials. I've run low 80m dipoles 5-10 ft
off the ground when camping, and still had fairly
decent results to regional stations.
MK